Question

The inner diameter of a well is 2 m and it is 35 m deep. What would be the cost of cementing its inner wall at Rs. 500 per square meter ?

• A. Rs. 1,05,000
• B. Rs. 1,10,000
• C. Rs. 1,00,000
• D. Rs. 90,000

Answer 1

The correct option is B

Rs. 1,10,000

Inner radius of the well is $=\frac{2}{2}=1\text{m}$

Height of the well $=35\text{m}$

Inner area of the well = Curved Surface Area of the well

$=2\pi rh$

$=2\times \frac{22}{7}\times 1\times 35$

$=220{\text{m}}^2$

Cost of cementing = Area $\times$ Rate per square meter.

$=220\times 500$

$=\text{Rs.}1,10,000$